Concatenate a string to each object of an array

Question

I have an array looking like this:

myArray = [[EnterNode {name: "name1", _value_: 12.32 }],
           [EnterNode {name: "name2", _value_: 42.39 }],
           [EnterNode {name: "name3", _value_: 77.32 }],
           [EnterNode {name: "name4", _value_: 52.31 }],
           ...
]

I don't know what EnterNode means but this is how it looks like when I print it in the console.

I want to each _value_ to concatenate a string, for example " kg" so after this procedure the array to look like this:

myArray = [[EnterNode {name: "name1", _value_: "12.32 kg" }],
           [EnterNode {name: "name2", _value_: "42.39 kg" }],
           [EnterNode {name: "name3", _value_: "77.32 kg" }],
           [EnterNode {name: "name4", _value_: "52.31 kg" }],
           ...
]

I tries to do it like this:

myArray.forEach(_value_ => _value_ + " kg") but I get undefined as result.

Any suggestions?

Use .map instead of .forEach. Foreach doesn't return anything, whereas map returns a copy of the modified array — user184994
– user184994, Commented Dec 27, 2017 at 12:46
did it like that and my array contains now these: "[object Object] kg" — Leo Messi
– Leo Messi, Commented Dec 27, 2017 at 12:49
Not exact duplicate but should help you: stackoverflow.com/questions/16691833/… — Rajesh Dixit
– Rajesh Dixit, Commented Dec 27, 2017 at 12:53

gurvinder372 · Accepted Answer · 2017-12-27 12:48:37Z

1

myArray.forEach(value => value + " kg") but I get undefined as result.

Because you are not saving the value back to _value_ property of each item of the array

Make it

myArray.forEach( obj => ( obj._value_ += " kg" ) );

observe that iteration happens on the item of the array rather than _value_

Demo

var myArray = [
   {name: "name1", _value_: 12.32 },
   {name: "name2", _value_: 42.39 },
   {name: "name3", _value_: 77.32 },
   {name: "name4", _value_: 52.31 }
];

myArray.forEach( obj => ( obj._value_ += " kg" ) ); 
 
console.log( myArray );

answered Dec 27, 2017 at 12:48

gurvinder372

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